Complementary Metal-Oxide Semiconductor (CMOS) technology is commonly used to manufacture integrated circuits (ICs). Examples of modern ICs include microprocessors, microcontrollers, memories, voltage regulators, analog-to-digital and digital-to-analog converters, etc. Generally speaking, one or more components within an IC may operate based upon a voltage reference. To provide such a voltage reference, a voltage reference circuit may be designed within the IC.
An example of a voltage reference circuit is the bandgap circuit. A bandgap circuit is configured to output a temperature independent voltage reference with a value of approximately 1.25 V, or another value suitably close to the theoretical 1.22 eV bandgap of silicon at 0 K—that is, the energy required to promote an electron from its valence band to its conduction band to become a mobile charge.
In bandgap circuits, it is often necessary to tune the circuit to obtain highly accurate reference voltages. This tuning may be accomplished, for example, by trimming a resistor ratio or other voltage divider circuit into smaller steps.
The inventors hereof have recognized that in certain industries (e.g., automotive, etc.) tighter specifications have driven the need for higher accuracy voltage regulation. Several electronic parts now require fine trimming of bandgap circuits, which can take a relative long time during production. For instance, a bandgap circuit having 5 or 6-bit level and/or temperature slope calibration calibration may ordinarily require 1024 to 4096 voltage measurements (e.g., when trimming at two temperatures or more) to seek and find a suitable trimming code.